Not too much to go on is there???
One possibility:- You have installed a free "something" which incorporates a "nag" splash as part of being free. Assuming you have to register (or pay!) to remove the nag screen, then that's what you will have to do. If you want to delete QUOTE "It" UNQUOTE, go to Start > Settings > Control Panel > Add Remove Programs. Scroll until you find "it" and select Remove/Delete.